Anodised aluminium can be marked easily and beautifully with MOPA lasers. It can even produce a variety of grey tones, ranging from light grey to rich black. The best part? the short pulse durations won't ever drastically damage the surface of your material. The anodised layer is not removed, but instead it is repainted. Although the process is completely different from the production of annealing colours onto stainless steel, the results are somewhat comparable.
You can create very nice, crisp markings, particularly on anodised aluminium. Anodised aluminium is usually lasered as black. However, when combining conventional engraving (removal) with physically marking the anodised layer, your marking possibilities become endless.